U.S. patent number 7,419,012 [Application Number 11/588,862] was granted by the patent office on 2008-09-02 for wellbore top drive systems.
This patent grant is currently assigned to Varco I/P, Inc.. Invention is credited to James Edward Lynch.
United States Patent |
7,419,012 |
Lynch |
September 2, 2008 |
Wellbore top drive systems
Abstract
A drive system for wellbore operations, the drive system, in
certain, but not necessarily all aspects, including a main body, a
motor apparatus, a main shaft extending from the main body and
rotatable by the motor, the main shaft having a top end and a
bottom end, and an item, the item non-threadedly connected to the
main shaft.
Inventors: |
Lynch; James Edward (Terrell,
TX) |
Assignee: |
Varco I/P, Inc. (Houston,
TX)
|
Family
ID: |
38669502 |
Appl.
No.: |
11/588,862 |
Filed: |
October 26, 2006 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20080099221 A1 |
May 1, 2008 |
|
Current U.S.
Class: |
173/152; 175/218;
166/77.51; 166/77.1; 137/515 |
Current CPC
Class: |
E21B
19/16 (20130101); Y10T 137/7854 (20150401) |
Current International
Class: |
B23Q
5/00 (20060101) |
Field of
Search: |
;173/152,218,317
;175/214,218 ;166/77.1,77.51,85.1,85.3,86.1,325
;137/515,515.3,515.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truong; Thanh K
Attorney, Agent or Firm: McClung; Guy
Claims
What is claimed is:
1. A drive system for wellbore operations, the drive system
comprising a main body, a motor apparatus, a main shaft extending
from the main body and rotatable by the motor, the main shaft
having a top end and a bottom end, a connection assembly, an item,
the item adjacent to the bottom end of the main shaft and connected
to the main shaft with the connection assembly, the connection
assembly non-threadedly connecting the main shaft to the item, the
connection assembly comprising a load ring with a projection
projecting interiorly thereof, a load ring housing, the main shaft
having a recess therearound corresponding to the load ring's
projection, the projection disposed within the recess, and the load
ring housing connectible to an item below the main shaft and the
load ring housing adjacent and encompassing the load ring to
maintain the load ring in position with respect to the main
shaft.
2. The drive system for wellbore operations of claim 1 wherein the
drive system is a top drive system, and the main shaft is a drive
stem of the top drive system.
3. The drive system of claim 1 wherein the main shaft has an outer
surface, the recess has an interior wall, a lower fillet extends
from the interior wall to the outer surface of the main shaft, and
the lower fillet located for supporting the item and additional
things connected to the item.
4. The drive system of claim 1 wherein the item includes a drill
string.
5. The drive system of claim 1 wherein the load ring housing has a
series of spaced-apart wrench flats for facilitating rotation of
the load ring housing.
6. The drive system of claim 1 wherein the load ring housing has a
lower end with interior threading for threadedly mating with
exterior threading of the item.
7. The drive system of claim 1 wherein the load ring is comprised
of a plurality of at least two segments installable around and in
contact with the main shaft.
8. The drive system of claim 1 further comprising a series of
spaced-apart torque transmitting splines on the lower end of the
main shaft for engaging a series of corresponding splines on an
interior of the item.
9. The drive system of claim 1 wherein the load ring housing has a
lower end with interior threading for threadedly mating with
exterior threads of the item.
10. The drive system of claim 1 wherein the load ring is comprised
of a plurality of at least two segments installable around and in
contact with the main shaft.
11. The drive system of claim 1 further comprising a series of
spaced-apart torque transmitting splines on the lower end of the
main shaft for engaging a series of corresponding splines on an
interior of the item.
12. The drive system of claim 1 wherein the bottom end of the main
shaft is not threaded.
13. The drive system of claim 1 wherein the main shaft has a
longitudinal axis and a bottom surface at the bottom end, the
bottom surface normal to the longitudinal axis of the main shaft,
one of the main shaft and the item has a seal recess and an end
seal partially disposed in the seal recess, and the end seal for
sealing an interface between the main shaft and the item.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to wellbore drilling top drive systems
and methods of use; parts thereof; and, in certain particular
aspects, such systems with a top drive stem that is not threadedly
mated to an item connected thereto.
2. Description of Related Art
The prior art discloses a variety of top drive systems; for
example, and not by way of limitation, the following U.S. patents
present exemplary top drive systems and components thereof: U.S.
Pat. Nos. 4,458,768; 4,807,890; 4,984,641; 5,433,279; 6,276,450;
4,813,493; 6,705,405; 4,800,968; 4,878,546; 4,872,577; 4,753,300;
6,007,105; 6,536,520; 6,679,333; 6,923,254--all these patents
incorporated fully herein for all purposes.
Certain typical prior art top drive drilling systems have a derrick
supporting a top drive which rotates tubulars, e.g., drill pipe.
The top drive is supported from a travelling block beneath a crown
block. A drawworks on a rig floor raises and lowers the top drive.
The top drive moves on a guide track.
In many typical prior art top drive systems the top drive includes
a drive shaft or "stem" that is threadedly connected to an item
below it, e.g. a mud saver apparatus or an upper internal blowout
preventer. Improper handling or enormous stresses can damage the
threads on the end of the drive stem or shaft. Such damage can
result in personal injuries, costly down time for the rig, and
expensive replacement or repair of the drive stem.
In certain prior art systems, a standard method of attachment for
connecting the drilling pipe to a shaft, stem, power swivel or
standard swivel, is a threaded connection with a shoulder. The
nature of threads is such that the stress at the root of the thread
is high and often the thread is difficult to inspect for cracks. As
drilling loads increase (e.g., because the search for oil has gone
deeper and deeper in the earth), stresses in the threads of the
tool joint increase as well. Because of the nature of drilling
rigs, including those which drill while floating off shore, there
is sometimes a dynamic misalignment between the drive shaft and the
drilling pipe, which induces a moment into the threaded connection
in addition to the pressure, the drilling torque, and the support
of the drill pipe assembly. Because the drive shaft is rotating at
the time of the misalignment, there is an opportunity for the
accumulation of fatigue damage. This, if severe enough, will result
in the initiation and propagation of a fatigue crack. This can
result in the failure of the tool joint. A failure of the part
occurs when a fatigue crack has propagated to the outside of the
shaft. Once a failure occurs the rig is shut down to repair the
failed part. This represents lost income by reason of delays in
production and lost billable contractor hours.
Often drilling fluid is conducted through a drill stem requiring a
seal or seals between the drill stem and an item (e.g. an upper
internal blowout preventer) to which the drill stem is
connected.
There is a need for a more robust connection to the drive shaft or
stem of a top drive, swivel or power swivel, one less sensitive to
fatigue and easier to inspect. There is a need for an effective
structure for sealing an interface between a drive stem and an item
to which it is connected. There is a need for an effective
structure for transmitting torque from a drive stem to items below
it.
BRIEF SUMMARY OF THE INVENTION
The present invention, in certain aspects, provides a top drive
system for wellbore operations, the top drive system including: a
main body; a motor apparatus (e.g. one motor, or two or more
stacked or spaced-apart motors); a motor drive shaft (or stem)
extending from the main body, the drive shaft having a top end and
a bottom end, the bottom end having no threads; a connection
assembly which provides a non-threaded connection between the drive
shaft and another item; and, in certain aspects, an item (e.g., but
not limited to, a mud saver system, an upper internal blowout
preventer, a cross over thread adapter, a saver sub, a misalignment
coupling), the item non-threadedly connected to the drive shaft
with the connection assembly.
In one particular aspect, the drive shaft of the top drive motor is
connected to a drive stem and it is this stem that is
non-threadedly connected to another item. In certain aspects, this
other item is an upper internal blowout preventer that is
non-threadedly connected to the stem.
In certain particular aspects, a connection assembly according to
the present invention has a load ring adjacent a corresponding
recess in a drive shaft or a drill stem and the load ring is held
in place by a load housing. The load housing is threaded to
threadedly mate with another item below it. The load connected
beneath the drill shaft or stem passes through the load housing and
through the load ring. Thread damage, if it occurs, occurs in the
threads of the load housing which is relatively easily removed and
replaced at much less expense as compared to removing the shaft or
stem and replacing or repairing the shaft or stem.
In certain aspects, a second connection assembly according to the
present invention held in reserve allows the immediate replacement
of a connection assembly on site, thereby reducing the costs of rig
downtime by reason of a quick replacement. The original connection
assembly may then be cleaned and inspected at a convenient pace
(repaired if necessary) and set aside for the next field swapout
replacement once structural integrity is confirmed.
The present invention discloses, in at least certain aspects, a
drive system for wellbore operations, the drive system having: a
main body; a motor apparatus; a main shaft extending from the main
body and rotatable by the motor, the main shaft having a top end
and a bottom end; and an item, the item adjacent to the bottom end
of the main shaft and non-threadedly connected to the main
shaft.
The present invention discloses, in at least certain aspects, a top
drive system (e.g. top drive or power swivel) for wellbore
operations, the top drive system having: a main body; a motor
apparatus; a main shaft extending from the main body and rotatable
by the motor, the main shaft having a top end and a bottom end; an
item, the item non-threadedly connected to the main shaft, e.g.,
but not limited to, via exterior threading on the item. Optionally,
such a system has a connection assembly for non-threadedly
connecting the main shaft to the item, the connection assembly
having: a load ring with a projection projecting interiorly of the
load ring; a load ring housing; the main shaft having a recess
therearound corresponding to the load ring's projection, the
projection disposed within the recess; the load ring housing
threadably connectable to an item below the main shaft and the load
ring housing adjacent and encompassing the load ring to maintain
the load ring in position with respect to the main shaft, the load
ring housing has a lower end with interior threading for threadedly
mating with the exterior threading of the item. Optionally, any
such system may include a series of spaced-apart torque
transmitting splines on the lower end of the main shaft for
engaging a series of corresponding splines on the item.
The present invention discloses, in at least certain aspects, a
method for connecting a drive shaft of a wellbore operations drive
system to an item, the method including: positioning the drive
shaft of a drive system above an item, the drive system comprising
a main body, a motor apparatus, a main shaft extending from the
main body and rotatable by the motor, the main shaft having a top
end and a bottom end, and an item, the item non-threadedly
connectable to the main shaft; and connecting the drive shaft
non-threadedly to the item.
The present invention discloses, in at least certain aspects, a top
drive shaft useful in wellbore operations, the top drive shaft
having: a body having a bottom, a top, an exterior, and a fluid
flow bore therethrough from top to bottom; a load recess in the
exterior of the body; the load recess disposed for reception of a
load member; the load member releasably securable in the load
recess, e.g., but not limited to, by a housing, the housing
connectable to an item to be positioned below and supported by the
top drive shaft.
Accordingly, the present invention includes features and advantages
which are believed to enable it to advance drilling technology.
Characteristics and advantages of the present invention described
above and additional features and benefits will be readily apparent
to those skilled in the art upon consideration of the following
detailed description of preferred embodiments and referring to the
accompanying drawings.
Certain embodiments of this invention are not limited to any
particular individual feature disclosed here, but include
combinations of them distinguished from the prior art in their
structures, functions, and/or results achieved. Features of the
invention have been broadly described so that the detailed
descriptions that follow may be better understood, and in order
that the contributions of this invention to the arts may be better
appreciated. There are, of course, additional aspects of the
invention described below and which may be included in the subject
matter of the claims to this invention. Those skilled in the art
who have the benefit of this invention, its teachings, and
suggestions will appreciate that the conceptions of this disclosure
may be used as a creative basis for designing other structures,
methods and systems for carrying out and practicing the present
invention. The claims of this invention are to be read to include
any legally equivalent devices or methods which do not depart from
the spirit and scope of the present invention.
What follows are some of, but not all, the objects of this
invention. In addition to the specific objects stated below for at
least certain preferred embodiments of the invention, there are
other objects and purposes which will be readily apparent to one of
skill in this art who has the benefit of this invention's teachings
and disclosures. It is, therefore, an object of at least certain
preferred embodiments of the present invention to provide:
New, useful, unique, efficient, non-obvious top drive systems,
components and parts thereof, and methods of their use;
Such systems with a non-threaded shaft or stem connection between a
drive shaft or stem and an item below it;
Such systems with a connection assembly for non-threadedly
connecting a drive shaft or stem to an item therebelow, the
connection assembly including a load ring partially disposed in a
recess in the drive shaft or stem and a removable housing that
holds the load ring in place so that the load ring supports the
weight of items connected below the shaft or stem, including, but
not limited to, the weight of a drillstring below the stem;
Such systems which effectively seal an interface between the drive
shaft or stem and an item below the shaft or stem; and
Such systems transmit rotation to items below a drive shaft or stem
with a lower, non-threaded end.
The present invention recognizes and addresses the problems and
needs in this area and provides a solution to those problems and a
satisfactory meeting of those needs in its various possible
embodiments and equivalents thereof. To one of skill in this art
who has the benefits of this invention's realizations, teachings,
disclosures, and suggestions, various purposes and advantages will
be appreciated from the following description of preferred
embodiments, given for the purpose of disclosure, when taken in
conjunction with the accompanying drawings. The detail in these
descriptions is not intended to thwart this patent's object to
claim this invention no matter how others may later attempt to
disguise it by variations in form or additions of further
improvements.
The Abstract that is part hereof is to enable the U.S. Patent and
Trademark Office and the public generally, and scientists,
engineers, researchers, and practitioners in the art who are not
familiar with patent terms or legal terms of phraseology to
determine quickly from a cursory inspection or review the nature
and general area of the disclosure of this invention. The Abstract
is neither intended to define the invention, which is done by the
claims, nor is it intended to be limiting of the scope of the
invention or of the claims in any way.
It will be understood that the various embodiments of the present
invention may include one, some, or all of the disclosed,
described, and/or enumerated improvements and/or technical
advantages and/or elements in claims to this invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
A more particular description of embodiments of the invention
briefly summarized above may be had by references to the
embodiments which are shown in the drawings which form a part of
this specification. These drawings illustrate certain preferred
embodiments and are not to be used to improperly limit the scope of
the invention which may have other equally effective or equivalent
embodiments.
FIG. 1 is a schematic view of a top drive drilling system according
to the present invention.
FIG. 2A is a side cross-section view of a top drive stem according
to the present invention and of a top drive stem connection system
according to the present invention.
FIG. 2B is an exploded view of the stem and system of FIG. 2A.
FIG. 3A is a side view of the stem shown in FIGS. 2A and 2B.
FIG. 3B is a top view of the stem FIG. 3A.
FIG. 3C is a bottom view of the stem of FIG. 3A.
FIG. 3D is a bottom perspective view of the stem of FIG. 3A.
FIG. 4A is a side view of the load ring shown in FIGS. 2A and
2B.
FIG. 4B is a top view of the load ring of FIG. 4A.
FIG. 4C is a bottom view of the load ring of FIG. 4A.
FIG. 4D is a top perspective view of the load ring of FIG. 4A.
FIG. 5A is a side view of the load ring housing shown in FIGS. 2A
and 2B.
FIG. 5B is a top view of the load ring housing of FIG. 5A.
FIG. 6A is a side view of the upper internal blowout preventer
shown in FIGS. 2A and 2B.
FIG. 6B is a top view of the upper internal blowout preventer of
FIG. 6A.
FIG. 6C is a bottom view of the upper internal blowout preventer of
FIG. 6A.
FIG. 6D is a perspective view of the upper internal blowout
preventer of FIG. 6A.
FIG. 7 is a side cross-section view of a connection according to
the present invention.
FIG. 8 is a side cross-section view of a connection according to
the present invention.
Presently preferred embodiments of the invention are shown in the
above-identified figures and described in detail below. It should
be understood that the appended drawings and description herein are
of preferred embodiments and are not intended to limit the
invention or the appended claims. On the contrary, the intention is
to cover all modifications, equivalents and alternatives falling
within the spirit and scope of the invention as defined by the
appended claims. In showing and describing the preferred
embodiments, like or identical reference numerals are used to
identify common or similar elements. The figures are not
necessarily to scale and certain features and certain views of the
figures may be shown exaggerated in scale or in schematic in the
interest of clarity and conciseness.
As used herein and throughout all the various portions (and
headings) of this patent, the terms "invention", "present
invention" and variations thereof mean one or more embodiments, and
are not intended to mean the claimed invention of any particular
appended claim(s) or all of the appended claims. Accordingly, the
subject or topic of each such reference is not automatically or
necessarily part of, or required by, any particular claim(s) merely
because of such reference.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a top drive system 10 according to the present
invention which is structurally supported by a derrick 11. The
system 10 has a plurality of components including: a top drive 14,
(shown schematically) a main shaft 16, a housing 17, a drillstring
19 and a drill bit 20. The components are collectively suspended
from a traveling block 12 that allows them to move upwardly and
downwardly on rails 22 connected to the derrick 11 for guiding the
vertical motion of the components. Reactance to torque generated
during operations with the top drive or its components (e.g. during
drilling) is transmitted through a movable dolly or other support
(not shown) to the derrick 11.
The main shaft 16 extends through the motor housing 17 and connects
to items below the shaft ("stem" or "shaft"--"stem" can include
stems and shafts). The shaft 26 is non-threadedly connected to an
upper end of an IBOP assembly 24 which is the first in a series of
items and/or tubular members collectively referred to as the
drillstring 19. An opposite end of the drillstring 19 is threadedly
connected to a drill bit 20.
During operation, a motor apparatus 15 (shown schematically)
encased within the housing 17 rotates the main shaft 16 which, in
turn, rotates the drillstring 19 and the drill bit 20. Rotation of
the drill bit 20 produces an earth bore 21. Fluid pumped into the
top drive system passes through the main shaft 16, the drill stem
18, the drillstring 19, the drill bit 20 and enters the bottom of
the earth bore 21. Cuttings removed by the drill bit 20 are cleared
from the bottom of the earth bore 21 as the pumped fluid passes out
of the earth bore 21 up through an annulus formed by the outer
surface of the drill bit 20 and the walls of the bore 21. A typical
elevator 29 is suspended from the top drive system.
A variety of items can be connected to and below the main shaft 16;
for example, and not by way of limitation, the items shown
schematically as items 24 and 26 which, in certain aspects, and not
by way of limitation, may be an upper internal blowout preventer 24
and a lower internal blowout preventer 26. In other systems
according to the present invention the item 24 is a mud saver
apparatus, a load measuring device, a flexible sub, or a saver
sub.
A connection assembly 40 (any according to the present invention)
non-threadedly connects the item 24 to the main shaft 16. The shaft
16 may be a drill stem or a quill.
FIGS. 2A-6D illustrate a system 100 according to the present
invention for non-threaded connection of a drill stem (driven by a
motor of, e.g., a top drive) to another item, e.g. a mud saver
system or upper internal blowout preventer.
The system 100 has a drill stem 110 non-threadedly connected to an
upper internal blowout preventer 120 with a connection assembly 130
that has a load ring 140 and a load ring housing 150. The load ring
140 includes, in one aspect, two halves 140a, 140b.
The drill stem 110, which may be any suitable length, has a lower
end 112 above which is a circumferential recess 114. A series of
spaced-apart splines 116 project out from the lower end 112 of the
drill stem 110. A fluid flow bore 118 extends from the top to the
bottom of the drill stem 110.
The upper internal blowout preventer 120 has an upper end 122 with
threads 124 and a series of spaced-apart splines 126 which mate
with the splines 116 of the drill stem 110 to transfer torque from
the drill stem 110 to the upper internal blowout preventer 120. A
fluid flow bore 128 extends from the top to the bottom of the upper
internal blowout preventer 120 and is in fluid communication with
the bore 118. A seal 127 in a recess 129 seals the
upper-internal-blowout-preventer/drill-stem interface. The recess
129 is an upwardly-facing recess and the seal 127 abuts a lower
horizontal end surface (as viewed in FIG. 2A) of the drill stem
110. The seal 127 prevents the leakage of fluid flowing through the
upper internal blowout preventer and through the drill stem. Of
course, the recess may be on the end of the drive stem and the seal
may project down to sealingly contact an item connected to the
drive stem.
The load ring 140 has a projection 142 projecting inwardly from a
body 144 of the load ring 140. The load ring projection 142 (half
of which is on each load ring half 140a, 140b) projects into the
recess 114 of the drill stem 110.
The projection 142 is held in the recess 114 by the load ring
housing 150 which has interior threads 152 for threadedly mating
with the threads 124 of the upper internal blowout preventer 120 to
connect the load ring housing 150 to the upper internal blowout
preventer 120 and to maintain the load ring 140 in place. Loads
below the drill stem 110 are transferred to the load ring housing
150, from it to the load ring 140, and from the load ring 140 to
the drill stem 110, thus bypassing a lower part of the drill stem
110. A bore 158 extends through the load ring housing 150 to
accommodate the drill stem 110. Wrench flats 152 project out from
the housing 150.
FIG. 7 shows a system 200 according to the present invention (like
the system 100) which includes a driven shaft, a top drive stem
210, having a lower end 212 with a groove 214 having a groove wall
215, an upper fillet 216, and a lower fillet 218. The lower fillet
218 has a radius that is relatively larger than a typical radius of
a thread on certain threaded prior art top drive stems. This lower
fillet can withstand stresses higher than those which a typical
threaded top drive stem can withstand.
A load ring 220 has a projection 222 sized, configured, and located
for engaging receipt in the groove 214.
A housing 230 encompasses the load ring 220 and has a lower end 232
with interior threading 234. Wrench flats 236 project from the
housing 230.
The housing 230 is threadedly connected to an item (any disclosed
herein) beneath the housing 230. As shown, the item is an upper
internal blowout preventer 240 (shown partially) with an upper end
242 with exterior threading 244 that threadedly mates with the
threading 234 of the housing 230.
The general configuration of the system 200 results in a relative
increase in strength as compared to a typical connection with a
threaded stem. Stress on the stem is reduced due, e.g., to the
large radius of the lower fillet 218. The threading on the housing
230 and on the item below it (e.g. the IBOP 240) are easily
inspected and the housing 230 and ring 220 are relatively easy to
remove and replace.
FIG. 8 illustrates a system 100a according to the present invention
like the system 100 in FIG. 2A (like numerals indicate like
parts).
The system 200 has a drill stem 110a (driven by a motor of, e.g., a
top drive) non-threadedly connected to an upper internal blowout
preventer 120 with a connection assembly 130a that has a load ring
140a and a load ring housing 150. The load ring 140a includes, in
one aspect, two halves (e.g. like the halves 140a, 140b but with a
projection as described below).
The drill stem 110a, which may be any suitable length, has a lower
end 112. A series of spaced-apart splines 116 project out from the
lower end 112 of the drill stem 110a. A fluid flow bore 118 extends
from the top to the bottom of the drill stem 110a.
The load ring 140a has a recess 142a. A circumferential projection
110b of the drill stem 110a projects into the recess 142a.
Optionally, instead of a complete circumferential projection 110b,
one, two or more spaced-apart load member projections of sufficient
size and mass may be used; and/or with spaced-apart projections
instead of a ring only a corresponding load member recess (or
recesses) are provided.
The projection 110b is held in the recess 142a by the load ring
housing 150 which has interior threads 152 for threadedly mating
with the threads 124 of the upper internal blowout preventer 120 to
connect the load ring housing 150 to the upper internal blowout
preventer 120 and to maintain the load ring 140 in place.
Loads below the drill stem 110a are transferred to the load ring
housing 150, from it to the load ring 140a, and from the load ring
140a to the drill stem 110a, thus bypassing a lower part of the
drill stem 110a. A bore 158 extends through the load ring housing
150 to accommodate the drill stem 110. Wrench flats 152 project out
from the housing 150. FIG. 8 is not to scale. The internal diameter
(and total mass) of the load ring housing 150 may be increased as
needed for strength with a corresponding increase in load ring
size.
In certain aspects when assembled a drive stem connected to a lower
item (e.g. an internal blowout prevent) is maintained in a
condition so that a seal (or seals) sealing the stem/item interface
is maintained in sealing contact. Due to the weight that a drill
stem will support, this preload is provided, e.g., by a threaded
connection between a load ring housing and an internal blowout
preventer. In certain aspects, to maintain sealing, a preload force
is greater than the sum of the maximum vertical load to be imposed
on the stem and the separating force due to the pressure of fluid
that will flow through the stem forcing the stem apart from an
item, e.g. an internal blowout preventer. In one aspect, a wrench
is used to engage the lug protrusions (wrench flats) on the load
ring housing holding it stationary, while the drive stem is rotated
by drive motor(s) to make up the connection to the required
preload. Optionally bolts and corresponding holes on the two
apparatuses are used to apply the preload or an hydraulic ram is
applied and keeper key(s) are inserted to hold the two apparatuses
together under the preload.
The present invention, therefore, in at least certain embodiments,
provides a drive system for wellbore operations, the drive system
including: a main body; a motor apparatus; a main shaft extending
from the main body and rotatable by the motor, the main shaft
having a top end and a bottom end; and an item, the item adjacent
to the bottom end of the main shaft and non-threadedly connected to
the main shaft. Such a system may have one or some, in any possible
combination, of the following: a connection assembly for
non-threadedly connecting the main shaft to the item, the
connection assembly having a load ring with a projection projecting
interiorly thereof, a load ring housing, the main shaft having a
recess therearound corresponding to the load ring's projection, the
projection disposed within the recess, and the load ring housing
connectable to an item below the main shaft and the load ring
housing adjacent and encompassing the load ring to maintain the
load ring in position with respect to the main shaft; wherein the
drive system is a top drive system, and the main shaft is a drive
stem of the top drive system; wherein the main shaft has an outer
surface, the recess has an interior wall, a lower fillet extends
from the interior wall to the outer surface of the main shaft, and
the lower fillet located for supporting the item and additional
things connected to the item; wherein the item includes a drill
string; wherein the load ring housing has a series of spaced-apart
wrench flats for facilitating rotation of the load ring housing;
wherein the load ring housing has a lower end with interior
threading for threadedly mating with exterior threading of the
item; wherein the load ring is comprised of a plurality of at least
two segments installable around and in contact with the main shaft;
a series of spaced-apart torque transmitting splines on the lower
end of the main shaft for engaging a series of corresponding
splines on an interior of the item; wherein the load ring housing
has a lower end with interior threading for threadedly mating with
exterior threads of the item; wherein the load ring is comprised of
a plurality of at least two segments installable around and in
contact with the main shaft; a series of spaced-apart torque
transmitting splines on the lower end of the main shaft for
engaging a series of corresponding splines on an interior of the
item; wherein the bottom end of the main shaft is not threaded;
and/or wherein the main shaft has a longitudinal axis and a bottom
surface at the bottom end, the bottom surface normal to the
longitudinal axis of the main shaft, one of the main shaft and the
item has a seal recess and an end seal partially disposed in the
seal recess, and the end seal for sealing an interface between the
main shaft and the item.
The present invention, therefore, provides in at least some, but
not necessarily all, embodiments a top drive system for wellbore
operations, the top drive system having: a main body; a motor
apparatus; a main shaft extending from the main body and rotatable
by the motor, the main shaft having a top end and a bottom end; an
item, the item non-threadedly connected to the main shaft, the item
having an end with exterior threading; a connection assembly for
non-threadedly connecting the main shaft to the item; and a series
of spaced-apart torque transmitting splines on the lower end of the
main shaft for engaging a series of corresponding splines on the
item.
The present invention, therefore, in at least certain embodiments,
provides a method for connecting a drive shaft of a wellbore
operations drive system to an item, the method including:
positioning the drive shaft of a drive system above an item, the
drive system comprising a main body, a motor apparatus, a main
shaft extending from the main body and rotatable by the motor, the
main shaft having a top end and a bottom end, and an item, the item
non-threadedly connectable to the main shaft; and connecting the
drive shaft non-threadedly to the item. Such a system may have one
or some, in any possible combination, of the following: wherein the
drive system is a top drive system and the drive shaft is a top
drive stem; wherein the drive system includes a connection assembly
for non-threadedly connecting the drive shaft to the item, the
connection assembly having a load ring with a projection projecting
interiorly of the load ring, a load ring housing, the main shaft
having a recess therearound corresponding to the load ring's
projection, the projection disposed within the recess, the load
ring housing threadedly connectable to an item below the drive
shaft and adjacent the load ring to maintain the load ring in
position with respect to the drive shaft, the method further
including inserting the bottom end of the drive shaft into the
item, placing the load ring around the drive shaft with the
projection in the recess, placing the load ring housing over the
load ring, and connecting the load ring housing to the item;
wherein the main shaft has a series of spaced-apart torque
transmitting splines on the lower end of the main shaft, and the
item has a corresponding series of splines on an interior thereof,
the method further including transmitting torque from the main
shaft through the series of torque transmitting splines on the
lower end of the main shaft, through the corresponding series of
splines on an interior of the item, to the item; wherein the drive
shaft has a longitudinal axis and shaft fluid bore therethrough for
the flow of fluid through the drive shaft, the item has an item
fluid bore therethrough for the flow of fluid through the item, the
shaft fluid bore in fluid communication with the item fluid bore,
the drive shaft has a bottom surface at the bottom end, the bottom
surface normal to the longitudinal axis of the drive shaft, the
item has a seal recess and an end seal partially disposed in the
seal recess, the end seal sealingly contacting the bottom surface
of the main shaft, the drive shaft bottom end interfacing the item
at a shaft-item interface, the method further including preventing
leakage of fluid past the shaft-item interface with the seal;
and/or maintaining a preload on the driveshaft and the item to
maintain the seal in sealing contact with the drive shaft.
The present invention, therefore, in at least certain embodiments,
provides a top drive shaft useful in wellbore operations, the top
drive shaft having: a body having a bottom, a top, an exterior, and
a fluid flow bore therethrough from top to bottom; a load recess in
the exterior of the body; and the load recess disposed for
reception of a load member releasably securable in the load
recess.
In conclusion, therefore, it is seen that the present invention and
the embodiments disclosed herein and those covered by the appended
claims are well adapted to carry out the objectives and obtain the
ends set forth. Certain changes can be made in the subject matter
without departing from the spirit and the scope of this invention.
It is realized that changes are possible within the scope of this
invention and it is further intended that each element or step
recited in any of the following claims is to be understood as
referring to the step literally and/or to all equivalent elements
or steps. The following claims are intended to cover the invention
as broadly as legally possible in whatever form it may be utilized.
The invention claimed herein is new and novel in accordance with 35
U.S.C. .sctn. 102 and satisfies the conditions for patentability in
.sctn. 102. The invention claimed herein is not obvious in
accordance with 35 U.S.C. .sctn. 103 and satisfies the conditions
for patentability in .sctn. 103. This specification and the claims
that follow are in accordance with all of the requirements of 35
U.S.C. .sctn. 112. The inventors may rely on the Doctrine of
Equivalents to determine and assess the scope of their invention
and of the claims that follow as they may pertain to apparatus not
materially departing from, but outside of, the literal scope of the
invention as set forth in the following claims. All patents and
applications identified herein are incorporated fully herein for
all purposes.
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